:-D
He's glad Ianto doesn't fight the smile any more, because he likes seeing Ianto smiling. It happens a lot more nowadays than it once did, but it still seems pretty rare - a pure, uncomplicated smile like this.
He looks good in just the shirt and tie and smile. He'll look even better when he's bent over the desk, but Jack's not going to rush the kiss to get there. He keeps it going until he feels Ianto's hand go out to the desk, knowing it means he's melting nicely, and then he pulls back with a smirk and steps back, making a 'turn around' gesture with his hand while he leans over to retrieve one of the several bottles of lube strategically positioned throughout his office.